1. Field of Invention
The present invention relates generally to the field of beachhead preservation and particularly to methods and devices designed for prevention of beach erosion.
2. Related Art
Erosion of beaches due to waves displacing sediment has been an enduring problem, threatening coastal communities throughout the world. Apparatuses for preventing erosion of beaches, the bottoms and/or banks of rivers or streams, and/or for producing material deposits under water, are well-known in the art. Various techniques to prevent erosion are known in the art, as illustrated by the myriad of invention discussed herein. U.S. Pat. No. 5,888,020 details an apparatus including only a single truss system with gates, but fails to encompass the novel features of the instant invention, including multiple trusses.
U.S. Pat. No. 5,011,327 details an apparatus utilizing vertically stacked tiers of halved tires in order to reduce erosion as the tires allow water to pass through while causing solid matter present in the water to become trapped and build up over time. One of the disadvantages of this apparatus is the fact that it requires an entire array of tires for the trapping effect to work and this makes the apparatus more cumbersome. U.S. Pat. No. 5,795,099 discloses an apparatus that uses mesh flaps that will open when water is flowing toward a beach but will close when flowing the other direction. The mesh allows water to flow through but the holes in the mesh are small enough that sand cannot get through. The same disadvantage exists with this apparatus because it is also cumbersome as several mesh flaps connected together are the only way for the apparatus to work effectively.
U.S. Pat. No. 5,876,151 reveals an apparatus and method using a system consisting of rungs and viscous drag elements to trap sediment. Once again, this apparatus is cumbersome because it involves an entire system to be effective. U.S. Pat. No. 5,975,796 details a concrete mat that has non-abrasive surfaces for trapping sand. The disadvantage with this is that concrete is heavy and may cause damage to the beach that is different in nature from erosion.
U.S. Pat. No. 2,655,790 to Daley discloses a vertical permeable barrier wall formed in sections and mounted on a horizontal platform. The wall includes a series of flexible vanes fixed at their lower ends on horizontal axes and free to flex in either direction in response to wave or current flow, so that water flows through the wall in both directions upwardly to reduce the water's velocity, causing it to drop sediment at the base of the wall on both sides thereof.
U.S. Pat. No. 3,011,316 to Wilson discloses a breakwater having a pair of spaced-apart fences each with a plurality vanes, hingedly connected between posts so that they extend along horizontal axes. The purpose of Wilson's breakwater is to dissipate waves along the shores of bodies of water where the waves have a normal tendency to wash away the beach. The vanes are provided for dissipating waves traveling towards the beach.
U.S. Pat. No. 3,214,916 to Martin discloses a vertical wall assembly with gates hinged at their upper ends on horizontal axes on a beach side of the wall. The gates open toward the beach in response to incoming waves or current, and close in response to outgoing waves or current, to cause deposition of sediment between the wall and the beach. The wall is mounted on embedded posts and each gate carries a pivoted locking bar which embeds in accumulated deposits as they build up adjacent the bottom of the gate, thereby preventing the gate from thereafter opening in response to incoming waves or current and washing away the accumulated deposits.
Disadvantages of the systems described herein include expense in construction, structural failure due to the stress created by flow of water over time and starvation of sand from their downward drive, thereby negatively impacting the environmental sanctity of the marine life between the systems and the beaches, which they protect. Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.